Alternating-current system of distribution



(No Model.)

0. P. STEINMETZ.

ALTERNATING CURRENT SYSTEM OF DISTRIBUTION. N0.-559,913. Patented May 12,1896.

ANDREW ELGRAHAM. FNOTO-umfl WASHINGIOI. IJYC.

UNITED STATES PATENT OEEIcE.

CHARLES I. STEINMETZ, OF SCIIENECTADY, NEIV YORK, ASSIGNOR TO THE GENERAL ELECTRIC COMPANY, OF NEXV YORK.

ALTERNATING-CURRENT SYSTEM OF DISTRIBUTION.

SPECIFICATION forming part of Letters Patent No. 559,913, dated May 12, 1896. Application filed February 5,1896. Serial No. 578,152. (No model.)

To all whom it may concernwith Y connection and using a neutral or Be it known that I, CHARLES P. STEINMETZ, equalizing wire on the secondary side of the asubjeet of theEmperor of Germany, residing system only, and I have found that by this at Schenectady, in the county of Schenectady, arrangement so long as the primary voltages 5 State of New York, have invented certain new are constant the secondary potentials also are and useful Improvements in Alternating-Omconstant, irrespective of the balance of load rent Systems of Distribution, (Case No. 3353,) upon the secondaries. of which the following is a specification. The accompanying drawing shows a dia- My invention relates to the distribution grammatic embodiment of my invention, A 10 of alternating currents, particularly to polybeing a generator of three-phase current, a,

phase distributions. It has its most impor- Z), and 0 being the mains therefrom. tant application to three-phase systems, but D E F are the primary coils connected in others are not excluded. It has for its object delta; G II I, the secondary coils of the transto provide a means of equalizing the voltages former.

15 upon the several sides of the system, or of G H I are the inducing-coils of the threebalancing the lines, as it is often called. phase motor M.

It has been proposed to connect transformg h t' are the leads connecting the secondary ers wound for three-phase work with the Y coils and the motor-coils together, and k is the system of connection and to run a neutral neutral or equalizing wire.

20 wire from the common junction of the coils I thus not only obtain the advantage in back to the generator. here the secondatransmission of current at long distance of ries are also connected with the Y system, confining the equalizing-wire to the secondary this neutral wire on the primary side is a nedistribution only, but inasmuch as this may cessity, because, although a neutral may also be connected to fixed terminals upon the mo 2 5 be run from the secondary side, this will not tors I avoid the additional sliding contacts equalize the load, but with an unequal disalready referred to. tribution of load the three secondary voltages \Vhat I claim as new, and desire to secure will become unbalanced and greatly unequal. by Letters Patent of the United States, is 7 5 Nothing holds them at an equality, but on the 1. An alternating-current system of distrio contrary they change and adjust themselves bution, comprising transformers having their so as to be proportioned to the three second primaries connected in delta, and their secary currents.- The neutralizing-wire on the ondaries in Y, and a neutral or equalizing primary side running from the generator to wire extending from the common junction of the transformer must necessarily be of suflithe secondaries only.

5 cient cross-section to equalize the load, and 2. Agenerator oft-hree-phase currents,lines still it is normally an idle wire. This is of leading therefrom, a transformer having its course objectionable and deprives the threeprimaryconnected in delta between the lines, phase system when so installed of one of its a secondary for the transformer having the characteristic advantagesto wit, economy coils connected in Y, and an equalizing-wire 40 in copper cost. The generator also must be extending from the common junction of the specially constructed where this is done, insecondary coils.

asmuch as an additional sliding contact must In witness whereof I have hereunto set my be provided for the neutral wire. hand this 8d day of February, 1896.

To obviate the difficulties thus pointed out, CHARLES I. STEINMETZ. 45 I have devised my invention, which consists \Vitnesses:

in winding the primaries of the transformers B. B. I'IU LL,

with delta connection and the secondaries A. F. MACDONALD. 

